Field of the Invention
The field of the present invention relates to an apparatus and methods for plasma processing, and more particularly, to alternating current induced plasma processing for deposition, etching, or treatment of semiconductor, conductor or insulating films or carriers holding smaller substrates, rectangular substrates, or continuous band substrates.
Background
The development of plasma enhanced processes for deposition, etching, cleaning, and surface treatments have been instrumental to maintain the progress in many manufacturing industries, such as, integrated circuits (IC), liquid crystal display (LCD) screens, and photovoltaic (PV) panels.
Example reactors for plasma enhanced processing include parallel plate capacitive and microwave discharge reactors. Scaling reactors to process larger substrates may increase manufacturing cost because of the need to operate at lower power density and gas concentration per unit area to maintain desired film properties and uniformity.
For the IC and LCD industries, the cost of scaling plasma enhanced processes to larger substrates has been offset partially by the increased functionality per unit area (IC) and ability to charge a higher price for more surface area (LCD). The PV panel industry, on the other hand, faces additional challenges in finding ways to directly reduce manufacturing cost and energy use per unit area produced while also improving the deposition methods to produce panels with higher conversion efficiency of light to electrical energy. One method of manufacturing PV panels involves Plasma Enhanced Chemical Vapor (PECVD) deposition of silicon containing thin films.
However, bombardment by high-energy ions (>10 eV), formation of silicon particles in the gas phase, and metal contamination are factors that can contribute to defects in the deposited silicon films that reduce the efficiency of converting light to electrical energy. For many PECVD processes, it may be desired to achieve economical, high rate deposition, uniformity over large area substrates (including at edges and corners of large rectangular substrates) and efficient feedgas utilization.